Abstract: The fuel injection valve controller steadily detects the completion of opening of the fuel injection valve or the completion of the needle valve lifting movement. A current flowing through the electromagnetic coil 4 which drives the fuel infection valve, is measured based on the voltage difference V across the resistor R6 connected in series with the coil 4. The circuit 21 emphasizes changes in the coil current. The signal V2 representative of emphasized coil current is supplied to the current change detecting circuit 22 which generates the output signal V3 when the coil current or voltage signal V2 temporarily decreases. The signal V3 is compared with the reference voltage Vref to issue the signal S3 showing the full opening of the fuel injection valve.